


What Lies Beneath

by cookinguptales



Category: Little Witch Academia
Genre: F/F, mermaid au
Language: English
Status: Completed
Published: 2017-10-31
Updated: 2017-10-31
Packaged: 2019-01-22 14:58:17
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,986
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12484268
Author URL: https://archiveofourown.org/users/cookinguptales/pseuds/cookinguptales
Summary: A little mermaid washes up on a foreign shore. Thank goodness the Cavendishes are healers.





	What Lies Beneath

**Author's Note:**

  * For [ideallyqualia](https://archiveofourown.org/users/ideallyqualia/gifts).



> Hello, dear recip! I thought and thought about the best way to write a mermaid AU for you, and here it is!

The waves were choppy that day, and the water had gone a sickly blue-green. There had been a storm far away, her mother had said. They'd been spared the worst of it here in Wedinburgh, but somewhere out there too far for Diana's mind to fully process, an island nation had been battered by the waves. The water crashing against the rocks here had been in the tropics only days before. A storm could mix up the natural order of things, her mother had said. Could push back against the currents and eddies that had been there for hundreds of years and create a whole new normal.

Diana watched the waves of a foreign nation, and her fingers worried at her book's pages. She wasn't supposed to be out here, she knew. It was too dangerous now. She no longer had the magic of the Cavendishes to protect her. She was just one small girl with a wand that didn't quite work, and the waves were awfully big. But the sound of them, that loud-soft rhythm, was soothing. It eased the tiny hurts niggling at her heart, at least a little. She could just sit there by the rocks and read about the world of magic, a world that had been closed off to her for now, but whose lock she was determined to crack.

She was sitting there reading about beautiful, impossible things when it happened. The creature washed up on the rocks.

Now, it wasn't that Diana had never seen a bit of flotsam and jetsam on their beach. She'd combed the beaches before with her mother, clambering over rocks even as her mother taught her, in that gentle voice of hers, which of the sea plants could be used to bind wounds and break fever. She heard that voice in her mind now telling her to be wary of the ocean's gifts.

But she heard it again, another day and another lesson, telling her that Cavendishes were healers. They were kind and selfless and would do anything to help a soul in need. The creature, after all, was bleeding.

Diana carefully laid her book on the grass and started out across the rocks. They were precarious, to be sure, but she'd been picking her way across them for years. They were her home every bit as much as the stones that made up the castle. And there among them, gills flapping uselessly in the shallow tidal waters, was a fish. Or perhaps not a fish.

It was ugly, whatever it was.

Diana crept closer, her fingers knitting together a little nervously before she straightened her spine and put them down by her hips. Whatever this creature was, with its scale-slick body and a creepily human face, she knew that it needed help. And there was only her to help it. Her father was gone, her mother was sick in bed once again. And her aunt and her cousins, well... They wouldn't understand. They didn't know Beatrix the way she did. They couldn't.

"It's okay," she murmured even as she pulled her jacket from her shoulders. "I'll help you." She carefully soaked the fabric in seawater before bundling the little creature up in it and holding it gently to her chest. "Don't worry."

It had to be in water. She knew that much. But how did you bandage a fish? And what was the best way to offer aid to a magical creature when she no longer had magic running through her veins?

The library, she decided. She would put the fish creature in some water, then she would go to the library.

 

***

 

It took a while to get the fish creature situated. It was a very large castle and Diana's legs were very small. But the creature had opened one dark eye to gaze at her as its gills finally found purchase, and she'd felt her heart beat double-time as their eyes met. This was like something from one of her storybooks. From one of Chariot's shows. This was real magic, she felt it in her bones.

And the books that she'd come to depend on like breath, they'd only confirmed it. Non-magical healing had been the easy part; it was the identification of whatever the heck the little fish was that proved difficult. It wasn't until she'd started peeking through the old books, the ones weathered from disuse, that she found the barest scrap of information.

It was a mermaid. A real mermaid. Not the playful sirens from the fairytales, though, oh no. This was a mermaid from a faraway ocean, and it was a harbinger. (She'd looked it up. A 'harbinger' was nothing good.) Out on the islands where these mermaids lived, fishermen would throw them back in the water, would scrub at their hands to remove the taint. For these mermaids had powerful magic, but it only brought disaster to the humans who found them.

It was, in short, something that Diana probably should not have put in a fishbowl in her bedroom.

But even as she ran her fingers over the difficult words and shuddered at the illustrations, she remembered that double-beat of her heart. This was a magical creature. It had come to her even though she no longer had any magical ability. It was proof that she wasn't just some no-talent witch who'd burned too brightly and fizzled out fast. This was a creature in need, the kind of creature that the Cavendishes had sworn to heal to the best of their abilities no matter what.

This ugly little mermaid, it had to be a sign. A sign from Beatrix.

Even as her mind worried over the wisdom of taking a dark, magical creature into their home, her heart knew that she was doing the right thing. The only thing. She thought about the catastrophe that the book cautioned against -- the plague and famine and deep misfortune. She thought about water streaked red with blood and one dark, dark eye staring up into hers. She thought about the way her chest, small as it was, ached at the thought of throwing a mermaid back into the ocean.

And then she went to find the disinfectant.

***

There was a summer of Akko's life that she didn't remember, not well. She remembered when the storm came. She remembered the way her mother had tried to herd all the guppies to safety even as the water had drawn back in preparation for its onslaught. She remembered the sight of her home spiraling away from her as she was caught up in the most monstrous current she had ever known.

And she remembered kind, kind eyes and the sort of gentle touch that a person could only dream about. She remembered mixed-up murmurings and streaks of gold above the water, hanging down like sunbeams but as tangible as sea kelp. She remembered hope.

But the rest, the rest was darkness.

She'd found her way back home eventually. Her family had been convinced they'd never see her again. Their smallest, their youngest, their weakest. The one who'd been curiously clumsy lately, who'd started to seem more at home on the land than in the sea. It was as if all her radiance had been leached away, leaving her with a human body that worked well enough and a merform that had...issues. It had been no surprise that she'd been the one washed away by the Great Storm. The real shock had been when she'd come back, exhausted but still struggling her way to the shores they called home. She'd smelled of antiseptic and foreign hands. She'd stank of foreign magic.

But she was alive.

"That's our Akko," they'd all said, pulling her in close and feeling her scales against theirs. "Stubborn girl."

Akko was convinced that she'd been saved by a witch. Maybe even a beautiful, amazing one like Shiny Chariot. Were all witches so amazing? God, she hoped so. Her life had been twice touched, once saved, by human magic. Was it any real surprise that she became obsessed with it?

We have our own magic, she'd been told. We _are_ magic. But she didn't care about that kind of magic anymore, the kind that bubbled within. She didn't care that her flesh held immortality. She wanted to hold a wand in her hands and race into the sunset on a broom. She wanted to fly out of the water and into the sky. She wanted to make the world smile just like Shiny Chariot had.

And more quietly, more secretly, she wanted to meet the young witch who'd saved her life. She'd imagined her a thousand times before she even hit puberty. How old was she? How small, how tall? Was she beautiful? She had to be beautiful; Akko had sensed it. She was certainly kind.

Akko wanted to thank them both. They'd both changed her so irrevocably. They could probably teach her so much. She was so grateful.

And when she made it into Luna Nova with falsified documents and the quiet _look human, act human, walk and talk and breathe human_ mantra racing through her head, she knew she'd come home.

 

***

 

Diana Cavendish didn't have all that many regrets, but saving the life of one small fish was one of them. In her child's mind, "catastrophe" meant something huge. Lightning from the sky or a plague on the entire island. Those things had seemed highly unlikely to happen because of a little fish. The risk, back then, had seemed worth it.

And then her mother had died, and the Cavendish family had fallen into ruin. Debts seemed to surface every day, and Daryl surveyed them with a mouth drawn up tight and eyes gone wide and greedy. It had been the beginning of the end.

There had been no plague. There had been no war or famine or storm. But there had been a catastrophe all the same, and Diana's life had never been the same.

There were nights that Diana found herself gazing into the fire, a dozen books open beside her and a wand clenched tight in her hand, that she thought maybe it was a coincidence. Maybe saving the fish hadn't really cursed them all. Maybe her mother was already sick, maybe the debts had already been hidden away, maybe Daryl was already poised to strike. Maybe all the cogs in the machine of her undoing were already made. But maybe it was her little fish that had set the whole mess in motion.

Maybe it was Diana's childhood folly that had doomed them all.

No one had said a word when Diana's "pet fish" went missing at the end of the summer. There had been bigger problems by that point; her mother had taken a turn for the worse and no one knew who would be taking power once she was gone. No one noticed one little girl with red-rimmed eyes and nail-bitten fingers tipping a healthy fish into the ocean. Why would they? No one had cared. Only Diana knew what she had done, and the guilt of it, the horror and sadness and shock, stuck there in the back of her throat for years to come.

It was, to put it mildly, a kick in the pants. Diana had always known that she would one day lead her family. She knew that they needed her to be strong and smart and responsible. They needed her to be skilled at magic. And she'd read so much, had practiced so hard. But none of it had seemed quite real until the day her mother died and Diana knew with all her heart that she'd fucked up.

Two hours of training became six, became more. The books next to her bed, a mishmash of spellbooks and fantasy, became orderly stacks of magical theory and history. While the other children her age were playing and flirting and going out to parties on weekends, Diana was studying dead languages and arcane mysteries.

And that, she didn't regret. It was her love of fancy that had gotten them all into this mess, after all. So now it was time to put away those childish loves, the magical creatures and the breathtaking illusions and _Shiny Chariot_ , and put herself to work. It was the least she could do, after all. The very, very least. She had to be responsible now, like she hadn't been before. She had to save her family from a disaster of her own creation.

The one treat she allowed herself, silly as it was, was Luna Nova. She told herself that she'd have incredible research opportunities there, but she knew the truth. A small part of her heart still wanted to go where Shiny Chariot had gone; it wanted to see beautiful spells and have broomstick races and learn to make potions with new friends. It was the small, stupid part of her that didn't regret saving the life of one little fish.

It was a selfish indulgence, she knew, but it really was magical. She felt Chariot there in every brick, every winding sprig of ivy, every impossible thing she witnessed right before her eyes. And there were other miracles, as well.

She met a girl who was so like her and so different. She could see her own childhood struggles reflected back at her whenever she looked in Atsuko Kagari's eyes, and the sight of them made her wince. But Atsuko didn't deal with them the same way. She didn't buckle down and work, harder and harder and harder again. She played. She laughed. And her magic, when it worked, was the most beautiful that Diana had ever seen.

It made her heart feel bruised and sore when she watched Akko play with the magic that Diana had always needed to take deadly seriously. It beat double time, thrilled at the beauty of it, but little pinpricks of jealousy bled away the joy she should have felt. It felt a little bit like the memories of her mermaid. Impossible and amazing and utterly incongruous with the realities of her life.

Diana held Akko at arm's length as she buried herself in her studies. The loveliest distractions were the most dangerous, she'd learned.

 

***

 

Akko loved Luna Nova. She loved it. She loved its mysteries and its dangers, its beauties and its disappointments. She could feel herself growing every day, with bandages and bruises as proof, and every night when she dreamt, she woke up feeling that they were ever closer to reality.

As lovely as the school was, though, as much as she loved her friends and their adventures and the sense of wonder pervading every single thing she did, there were some downsides. The mountains of homework. The strictest of teachers. Blonde-haired snoots who could never seem to leave well enough alone.

The sailors back home told stories about witches, how they'd reel you in with magic and then bleed you dry. And Diana, Diana was a witch to her core. She was beautiful and refined, powerful and elegant. And a total jerk.

Akko hated that she always seemed to be there, right at the edge of her eyes, doing everything _right_. Doing the lessons right. Making friends right. Being the perfect image of a storybook witch. She hated that she couldn't take her eyes off her any more than the others could. One glimpse of blonde hair could have her feeling the strangest sensation, nostalgia for a person she didn't even know yet, and the itchy feeling of it beneath her skin just made her angrier than ever.

"That Diana!" she huffed even as she paced between her friends. "She thinks she's so great! Just because she can levitate things correctly!"

"And not blow up the classroom..." Sucy muttered quietly.

Akko ignored her. "I bet there are some things I could do better than her!" she insisted. Swimming, for one, though that had been forbidden fruit since she'd come to Luna Nova. Or maybe self-transformation.

"You're certainly good at causing trouble," a lilting voice came from behind her, and _what the heck._

"I didn't ask you, Diana!" she snapped.

"Oh? You kept saying my name, so I wasn't sure."

Akko felt her cheeks go red, the heat rising in her head and her heart, the pressure of it making the corner of her eyes sting. She hated her, but she liked her, too. She hated that they were so far apart. She hated that Diana thought she was so much better than her. She hated that Diana might be right. She hated that all of the best witches in school looked down at her like she'd never amount to anything.

They didn't know her. They didn't know her at all. They didn't know any of the things she could do. Or any of the things she'd done. They'd never know that she swam across the entire ocean or that she'd braved a typhoon all by herself. They'd never know how scary it was to be the first mermaid in her family to become a witch, nor would they know the sick feeling in her stomach when she thought that she might not even be good at that.

A failure as a mermaid. A failure as a witch. She knew what they saw when they looked at her.

But Akko bristled, planted her legs and went as tall as she could. "Just bug off, Diana! No one would be saying your name in a good way!"

She'd show Diana. She'd show her teachers and her friends and all the other people who thought that this clumsy beginner witch was all she'd ever be.

She'd show them all that a mermaid had teeth.

 

***

 

Time passed. Things changed. Diana had thought that her future was written in stone now that she was needed to lead the Cavendishes. She'd thought, in no small part, that it'd been her restitution. But maybe restitution could only come after a life well lived. Maybe she needed more experience before she could pull the Cavendishes out of the hole they'd fallen into.

And maybe, maybe sins were never quite as egregious as they first looked.

The adventure that she and Akko had shared had been, among other things, wet. Diana hadn't noticed it at first; she'd been much more focused on the future and livelihoods of everyone she'd ever loved. But their castle was surrounded by water, and its icy spray had soaked her and Akko to the bone by the time they trudged back to Diana's room, quiet and aching and stunned silent.

Diana was used to that. She'd grown up by the sea, after all. She didn't think much of it as she removed her sodden cloak and turned to help Akko with her own wet clothes. Until she saw the scales.

"What are those?" she asked. There was a horrible suspicion rising up in her mind like the tide on rocks, but it didn't disquiet her. Not like it would have before. Maybe she was too tired to be scared, to be angry. Maybe things had just changed.

Akko, more than anyone else, was a person she could trust. Even if she was gleaming in the lamplight.

"What?" Akko asked blankly, then looked down at her own skin. She squeaked, a thoroughly alarmed sound that Diana didn't know how she had the energy to make, and quickly tried to pull her sleeves down to cover as much as possible. "It's -- it's nothing! Just a little wet from the... the water!"

"Akko," Diana said.

"No, really!" Akko said, waving her arms quickly, apparently forgetting that she'd been trying to use her sleeves to cover anything. "Maybe just a little salty!"

Diana remembered what it had been like, all those years ago. Watching thick clouds fall away as the storm receded, seeing the sun peeking through like a lifeline. She felt a little bit like that now. Like a cloud that had been hovering over her for her entire life was just starting to dissipate. "You know," she said, quiet, "You remind me a little bit of a goldfish I had once."

"A what?" Akko put down her arms, looking a little offended now. "A goldfish?"

"Yes," Diana said. What had she done with that fishbowl, anyway? "One that I found in the sea and nursed back to health."

"I'm not a stupid go--" And then the words died in her mouth. She looked at Diana, those silly, over-expressive eyes gone very wide and very shiny. Akko wasn't nearly as stupid as she made herself out to be. Diana knew that now. She could see the wheels working in that head of hers.

"No, you're not," Diana said, and crossed her arms. "You're not a witch, either, are you?"

Akko's lips went down together in a tight line. "I am! I'm just as much a witch as anyone else! You don't -- no one ever said you had to be fully human to be a witch! I know! I checked!" she said.

Diana raised an eyebrow. That did seem like exactly the kind of loophole Akko would catch. "But you're not denying that you're a mermaid."

"I--" Akko's mouth snapped shut, like she'd all the sudden realized what she'd accidentally admitted. "I... Maybe."

Diana thought about all the tragedies that had befallen her family since she'd saved the mermaid. Her mother slowly wasting away to nothing. Her aunt's tyrannical rule. Their treasures being lost to the ages, to private collections and greasy hands and greed. The loss of her own innocence at such a young age. And then she thought of Akko. Sweet Akko. Bright Akko. The girl who'd driven her mad and then brought her right back to the self she'd always wanted to be. The girl whose strange magic felt like the mirror image of her own -- or maybe a reflection in water, a little wavy, a little unknown.

Akko, who always seemed to bring bad luck everywhere she went... and the uncanny ability to fix whatever she'd broken.

Diana felt broken. She felt fixed. She wondered if curses even truly existed in the first place. If they did, how could someone like Akko set them in motion?

"Tell me," she said, and she could feel her heart beating hard in her chest. "Is it true that Japanese mermaids bring bad luck?"

Akko's mouth dropped open and her eyebrows went down. "Bad _luck?_ Who told you that? We're good luck, okay? Good luck! My mom has good luck and my dad has good luck and I even hear that we can make humans _immortal_ if they take a taste, so--"

Diana, blood burning hot and skin prickling, took a taste. Akko didn't taste much like immortality. She didn't even taste like luck or hope or any of the other wonderful things that Diana seemed to feel when Akko was around. But the kiss itself was nice, once Akko stopped yelling and started getting with the program.

"You're the one," Akko said, a little dazed as Diana pulled away. "The one who saved me in the storm."

"Cavendishes heal anyone who comes to their door," Diana said. "Even bad luck goldfishes." It was what made them who they are. It was what made them strong. It was what helped them find their fates.

Akko was flushed red again, but this time she didn't look angry. She was edging closer, head tilted upwards in a silent request. "I've wanted to talk to you for a long, long time," she said, and her voice was uncharacteristically wobbly.

"And say what?" Diana asked, taking Akko's hand in hers.

Akko just smiled at her, and it was all magic and sunlight and the sweet freedom that Diana had always hoped in the back of her mind she'd find at Luna Nova. "Thank you," she said, and then leaned in for another kiss.


End file.
